PET-CT

What is it? Why is it used?

A PET/CT scan is an effective way of revealing or evaluating several conditions, including many cancers, heart disease and brain disorders. It often detects disease before it shows up on other imaging tests or when standard tests are inconclusive. This type of information can be life-changing and helps physicians improve treatment planning for their patients. 

A PET/CT scan uses a radioactive drug (tracer) to identify areas of your body that have higher levels of chemical activity, which often correspond to areas of disease. On a PET/CT scan, these areas show up as bright spots. PET detects changes in cellular metabolism (how active a cell is), often indicating the presence of disease. CT detects changes in the physical size or shape of a lesion and shows exactly where in the body the lesion is located.

Cancer

Cancer cells show up as bright spots on PET scans because they have a higher metabolic rate than do normal cells. PET scans may be useful in:

  • Detecting cancer
  • Revealing whether your cancer has spread
  • Checking whether a cancer treatment is working
  • Finding a cancer recurrence
  • PET scans must be interpreted carefully because noncancerous conditions can look like cancer, and some cancers do not appear on PET scans. Many types of solid tumors do appear on PET scans, including:
    • Brain
    • Cervical
    • Colorectal
    • Esophageal
    • Head and neck
    • Lung
    • Lymphoma
    • Melanoma
    • Pancreatic
    • Prostate
    • Thyroid
    • Prostate Cancer
PSMA-PET scans hunt for cancer that is spreading, or metastasizing in men with rising PSA levels after prostate cancer treatment, or if cancer is suspected of metastasizing in a newly diagnosed patient. The scans are able to detect tumors only a few millimeters in size anywhere in the body, they allow doctors to find and treat metastases before they become more dangerous.

PET measures the metabolic and functional activity of the heart, the presence and distribution of damaged or dead heart muscle, and the selection and monitoring of appropriate interventions, including cardiac surgery.  PET/CT scans are uniquely suited to detect infections or inflammation in the heart muscle, valves, or blood vessels, including infections or replacement valves or of implanted device such as pacemakers.  PET/CT in cardiology is used in the following areas: 

Cardiac Sarcoidosis

  • May be suspected in non-ischemic heart failure
  • Diagnosis when MRI equivocal
  • Detection of extracardiac manifestations
    • Lung
    • Bone
  • Monitoring response to therapy 


Infectious and Inflammatory conditions including:

  • Vasculitis 
  • Endocarditis
  • Implanted devices infection
  • Vascular graft infection
  • Suspected inflammatory/infectious myocarditis


PET/CT in the Diagnosis and Workup of Sarcoidosis: Focus on Atypical Manifestations | RadioGraphics

Heart Disease

Brain Disorders

PET/CT scans can be used to evaluate certain brain disorders, such as:

Cognitive Impairment

  • Differential, early (before change on MRI) diagnosis of dementia:
    • Mild cognitive impairment): AD vs non-AD
    • Alzheimer’s Disease
    • Vascular dementia
    • Frontotemporal dementia
    • Dementia with Lewy bodies
  • Excellent prognostic value in a negative test


Study: PET/CT of Dementia

Traumatic Brain Injury

Demonstration of abnormal metabolic findings even with normal MRI anatomy

  • Metabolic abnormalities correlate with mechanism of injury
  • Findings correlate with abnormalities demonstrated on neuropsychological testing


FDG PET in traumatic brain injury

Epilepsy

  • Interictal FDG PET has high sensitivity for extra-temporal epilepsy
  • Detection of temporal lobe epilepsy despite normal MRI
    • “MRI-negative PET-positive” temporal lobe epilepsy


PET studies in epilepsy

By the Numbers

50%

A recent Canadian study by Worsley et al. (2010) found that the information derived from PET imaging resulted in a change in intended treatment plans in 50% of cases (1).

70%

PET imaging allows physicians to avoid costly biopsy surgeries in as many as 70% of cases (1).

$60,544

A study comparing different staging techniques for patients with esophageal cancer found PET-based diagnostic imaging to have a cost-effectiveness ratio of USD $60,544 per quality-adjusted life year (QALY) (7).

Role Within Health Care Systems

While PET/CT scanners have been predominantly used in oncology, they are now increasingly used in various disciplines such as general internal medicine, infectious diseases, cardiology, neurology, surgery, traumatology, orthopedics, pediatrics, endocrinology, rheumatology, psychiatry, neuropsychology and cognitive neuroscience … and many jurisdictions have begun to expand the publicly funded indications for PET/CTs to include many non-cancer indications.

Rapid Synthesis, McMaster University, 2018
At INITIO, we firmly believe that health care in B.C. can be the best in the world. That’s why, through our clinic, we’re proactively investing in advanced molecular (personalized) imaging, such as PET/CT and radionuclide therapeutics, in order to support the public health care system and the health of every British Columbian and Canadian.

2

The World Health Organization recommends that countries should have 2 PET/CT scanners per million people. PET/CT is used for various indications including oncology, neurology, and cardiology.

0.62

There are only 0.62 PET/CT scanners per million people in British Columbia. In B.C., PET/CT imaging is not provided for non-cancer indications.

2.24

There are 2.24 PET/CT scanners per million people in Australia. In Australia, PET/CT is used for various indications including oncology, neurology, and cardiology.

What is the risk?

  • It is similar in terms of safety to diagnostic procedures found in radiology (e.g. X-rays, MRIs)
  • Millions of PET scans have been performed worldwide.
  • The exposure level to radiation is very small and is considered safe for a medically-appropriate diagnostic procedure.
  • The radioactive tracers used in PET/CT disappear from your body completely within 24 hours.
  • We employ all safety measures and safety equipment and are happy to provide more information about any of our procedures.

Are you or a loved one considering a PET/CT scan?

We know that making decisions about medical procedures can be stressful, and we want you to be informed and empowered in your choices. As such, these forms are here to guide you regarding how to determine if a PET/CT is right for you or a loved one, and what the process will be like.